Nonresonant Raman control of ferroelectric polarization

TL;DR

This paper demonstrates a novel ultrafast, low-energy method using nonresonant Raman excitation with mid-infrared pulses to reversibly control ferroelectric polarization in lithium niobate, enabling access to hidden phases.

Contribution

It introduces a new nonresonant Raman technique employing ultrashort mid-infrared pulses to induce ferroelectric switching, surpassing previous perturbative approaches.

Findings

Successfully induced ferroelectric reversal in lithium niobate.

Characterized large-amplitude mode displacements via femtosecond stimulated Raman scattering.

Validated the approach with first-principle calculations.

Abstract

Important advances have recently been made in the search for materials with complex multi-phase landscapes that host photoinduced metastable collective states with exotic functionalities. In almost all cases so far, the desired phases are accessed by exploiting light-matter interactions via the imaginary part of the dielectric function through above-bandgap or resonant mode excitation. Nonresonant Raman excitation of coherent modes has been experimentally observed and proposed for dynamic material control, but the resulting atomic excursion has been limited to perturbative levels. Here, this challenge is overcome by employing nonresonant ultrashort pulses with low photon energies well below the bandgap. Using mid-infrared pulses, ferroelectric reversal is induced in lithium niobate, and the large-amplitude mode displacements are characterized through femtosecond stimulated Raman scattering and second harmonic generation. This approach, validated by first-principle calculations, defines a novel method for synthesizing hidden phases with unique functional properties and manipulating complex energy landscapes at reduced energy consumption and ultrafast speeds.